comparison vamp-sdk/FFT.h @ 337:d5c5a52e6c9f

Make the simple base-fft implementation accessible for use by plugins as well. Bump version to 2.4

+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    Vamp
+
+    An API for audio analysis and feature extraction plugins.
+
+    Centre for Digital Music, Queen Mary, University of London.
+    Copyright 2006-2012 Chris Cannam and QMUL.
+  
+    Permission is hereby granted, free of charge, to any person
+    obtaining a copy of this software and associated documentation
+    files (the "Software"), to deal in the Software without
+    restriction, including without limitation the rights to use, copy,
+    modify, merge, publish, distribute, sublicense, and/or sell copies
+    of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be
+    included in all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+    NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
+    ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
+    CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+    WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+    Except as contained in this notice, the names of the Centre for
+    Digital Music; Queen Mary, University of London; and Chris Cannam
+    shall not be used in advertising or otherwise to promote the sale,
+    use or other dealings in this Software without prior written
+    authorization.
+*/
+
+#ifndef _VAMP_FFT_H_
+#define _VAMP_FFT_H_
+
+#include "plugguard.h"
+_VAMP_SDK_PLUGSPACE_BEGIN(FFT.h)
+
+namespace Vamp {
+
+/**
+ * A simple FFT implementation provided for convenience of plugin
+ * authors.
+ * 
+ * This class provides double-precision FFTs in power-of-two sizes
+ * only. It is slower than more sophisticated library
+ * implementations. If these requirements aren't suitable, make other
+ * arrangements.
+ *
+ * The inverse transform is scaled by 1/n.
+ *
+ * The implementation is from Don Cross's public domain FFT code.
+ */
+class FFT
+{
+public:
+    /**
+     * Calculate a forward transform of size n.
+     *
+     * ri and ii must point to the real and imaginary component arrays
+     * of the input. For real input, ii may be NULL.
+     *
+     * ro and io must point to enough space to receive the real and
+     * imaginary component arrays of the output.
+     *
+     * All input and output arrays are of size n.
+     */
+    void forward(unsigned int n,
+		 const double *ri, const double *ii,
+		 double *ro, double *io);
+
+    /**
+     * Calculate an inverse transform of size n.
+     *
+     * ri and ii must point to the real and imaginary component arrays
+     * of the input. For real input, ii may be NULL.
+     *
+     * ro and io must point to enough space to receive the real and
+     * imaginary component arrays of the output. The output is scaled
+     * by 1/n. The output pointers may not be NULL, even if the output
+     * is expected to be real.
+     *
+     * All input and output arrays are of size n.
+     */
+    void inverse(unsigned int n,
+		 const double *ri, const double *ii,
+		 double *ro, double *io);
+};
+
+}
+
+_VAMP_SDK_PLUGSPACE_END(FFT.h)
+
+#endif